water that would be available before the further reaches of the canal were built,
how will it be taken away from them?

Irrigation: Conclusions

It is clear that the irrigation benefits of the SSP have been vastly
exaggerated. The project will not only be unable to irrigate 1.8 million ha, it
may have water to reach only 44-52% of that area. Large parts of the command
are unsuitable for irrigation, and waterlogging and salinisation are bound to
occur. Prospects of failure loom large, magnified by the absence of the
Narmada Sagar Project. Rich and powerful central Gujarat will definitely
benefit in the short run, before waterlogging and salinisation lays waste its fields
forever, but the drought-hit will be left high and dry.